The construction and more particularly the maintenance, repair or replacement of roof structures in large industrial buildings such as factory roofs presents numerous problems, particularly with ensuring the safety of workers. For example, factory roof structures sometimes need major work including replacement as a result of deterioration after years of use. Some factories produce or use corrosive substances which are present in the atmosphere in the factory and which, over periods of time, can cause severe corrosion of roof structures including the roofing materials and the support structure for the roofing materials including particularly roof purlins. Such corrosion and deterioration of roofing materials and the roof support structure can make it particularly dangerous to attempt to repair or replace the roof structure by walking on the roof. To solve this problem it has been usual in the past to erect scaffolding within the factory to enable the maintenance or replacement of the roof structure by workmen supported by the temporary scaffolding erected for the purpose. However, the erection and disassembly of such scaffolding can be time consuming and expensive and can substantially interfere with normal operations in the factory.
Although not widely and commonly known, the work platform for roof construction work disclosed in U.S. Pat. No. 6,267,201 which is equivalent to Australian patent specification AU-707069 includes an upper work surface mounted by a structural frame, the work surface having removable sections provided in a walkway extending around the perimeter of the frame enabling a worker to carry out work on the area of the roof structure below a removed section. This work platform has mounting feet and fastening means associated with the mounting feet so that the platform can be secured to the roof structure and, at the end of the required work being performed, the fastening means can be released to enable the platform to be moved to another work position on the roof structure or returned to the ground level.
The work platform in U.S. Pat. No. 6,267,201 and AU-707069 is manufactured, or at least is modified, for each particular work site. The work platform is of substantial size and mass. Therefore the construction and use of this work platform can be relatively costly. For roof construction work on smaller buildings (including industrial, commercial, and domestic buildings) or even for smaller maintenance jobs to be carried out on small or larger buildings, there is no need for such a relatively large product as disclosed in that patent, nor for the need to achieve the desired function to specially manufacture and/or modify apparatus for the purpose. Similarly the expense associated with manufacturing and/or modifying apparatus such as disclosed in that patent would not be needed or indeed desirable for smaller buildings and/or smaller jobs. Furthermore, a particular roof construction task may involve working with a building (including relatively large as well as smaller buildings) where the roof support structure on which the work platform of that patent would be mounted may not be suitable for receiving and/or supporting such a work platform.
There are other areas also where performing work operations is carried out at elevated work stations. One example is in the performance of repair, maintenance, servicing, and dismantling or disassembly work performed on vehicles, particularly aircraft, particularly large passenger aircraft where work operations need to be performed from atop the aircraft fuselage. In this situation, not only are the workers at an elevated position requiring safety measures to avoid workers falling from the work station, but also the substantial weight should not be brought to bear on the skin or panels or framework of the fuselage and the risk of damage to the aircraft by apparatus being used must be minimised. It is known to provide scaffolding-like structures which can be moved into and out of position, but these can be expensive cumbersome and bulky. It is also known to enable access to an aircraft fuselage for work operations, from overhead positions by providing gantry frames which can be moved into and out of position. These require large aircraft hanger space where the gantries are suspended from the roof structure of the hanger.
Yet further areas of application of work platforms enabling access to elevated positions or access from above work object include large vehicles other than aircraft such as railway carriages, and parts of ships whether during construction thereof or at later times for maintenance, repair or servicing purposes. In these fields, accessing elevated work sites and performing work operations at such sites can be difficult and/or dangerous and/or the structures provided to enable access can be expensive, bulky, difficult and/or time consuming to manoeuvre or to arrange in position and remove after use.